The DESIREE facility

The experimental devices available at the DESIREE facility. Click on a photo for more information about the devices.

Ion List and Ion Sources

Ions on the following lists have been successfully produced and stored in DESIREE storage rings, a short description of each ion source is also attached below.

Atomic cations: H⁺, He⁺, B⁺, Li⁺, C⁺, N⁺, O⁺, F⁺, Ne⁺, Na⁺, Mg⁺, Si⁺, S⁺, K⁺, Ar⁺, Ar²⁺, Ar³⁺, I⁺, Xe⁺, Ba⁺, Fe⁺, Sm⁺

Atomic anions: H⁻, D⁻, O⁻,¹⁸O⁻, Si⁻, P⁻, S⁻, Cl⁻, Ni⁻, Cu⁻, Ge⁻, As⁻, Se⁻, Br⁻, Rh⁻, Pd⁻, Ag⁻, Sn⁻, Sb⁻, Te⁻, I⁻, Cs⁻, La⁻, Ir⁻, W⁻, Au⁻, Th⁻

Molecular cations: H₂⁺, HD⁺, D₂⁺, O₂⁺, N₂⁺, I₂⁺, NO⁺, HeNe⁺, HeH⁺, HeD⁺, H₃⁺, D₃⁺, H₃O⁺,

Molecular anions: CH⁻, CD⁻, CH₃⁻,¹³C₄H⁻,¹³C₆H⁻, CO₂⁻, CN⁻, OH⁻, OD⁻, O₂⁻, N₂O⁻, NO₂⁻, LaO⁻, SF₄⁻, SF₅⁻, SF₆⁻,¹⁶O¹⁸O⁻, HfF₅⁻, WF₅⁻, C₆H₄O₂⁻(para-Benzoquinone).

Molecular dianions: C₇²⁻,¹³C₇²⁻, C₉²⁻,¹³C₉²⁻, C₁₂²⁻, C₆₀²⁻,⁶LiF₃²⁻.

Cluster anions: C_2 − 15⁻, Cu_2 − 21⁻, Si₂⁻, Ag_2 − 3⁻, Au_2 − 15⁻

Complex ions: C₄H₄N₂⁺ (pyrimidine), C₉H₈⁺ (indene), C₁₀H₆O₂^- (1,4-Naphthoquinone), C₁₀H₈⁺(naphthalene, azulene), (C₁₀H₈)₂⁺ (naphthalene dimer), C₁₀H₇CN⁺(cyanonaphthalene), C₁₀H₁₆⁺(adamantane), C₁₀H₁₆O⁺(camphor), C₁₄H₁₀⁺(anthracene, phenanthrene), C₁₃H₉N⁺ (acridine), C₁₂H₈N₂⁺ (phenazine), C₁₆H₁₀⁺(pyrene), C₁₇H₁₁⁺(methylene-pyrene), C₁₆H₉OH⁺(hydroxypyrene), C₁₆H₉Br⁺(bromopyrene), C₂₀H₁₂⁺(perylene), C₁₈H₁₂⁺(tetracene), C₂₄H₁₂⁺ (coronene), C₅₈⁺, C₆₀⁺, C₆₀⁻, C₇₀⁻, C₂₈H₃₁ClN₂O₃⁺(Rhodamine B), protonated phenylalanine and tryptophan.

Source of Negative Ions by Cesium Sputtering (SNICS)

As stated by its name, the SNICS is used to produce atomic, molecular and cluster anions from gaseous and solid targets, e.g., H, C, Si, Cn, etc. More information and specifications can be found at National Electrostatics Corp.

Electron Cyclotron Resonance Ion Source (ECRIS)

The monogan M-100 type ECRIS (2.45 GHz RF power up to 30 W) from PANTECHNIK can produce singly-charged cations from a variety of atomic and molecular gasses and vapours. A homemade oven (up to 700 ◦C) can produce vapour from the powder of, e.g., polycyclic aromatic hydrocarbons (PAH) and fullerenes.

Nielsen type Ion Source (NIS)

The NIS is a Nielsen-type hot filament Penning magnetron ion source. A detailed description of such a source can be found on pages 8 to 14 in this Licentiate Thesis. In the DESIREE laboratory, a homemade oven (up to 800 ◦C) is included, the NIS is often used to produce ions like Li, Na, Mg, etc.

Björkhage Ion Source (BjörkIS)

The BjörkIS at DESIREE is an electron-attachment-type ion source used to produce anions from PAHs and fullerenes, e.g., pentacene (C22H14) and C60. These anions are produced by the attachment of low-energy electrons to the gas phase parent species. The development of this source was inspired by this proceeding paper.

Electrospray Ionization (ESI) Source

A home-build ESI source is available on the high-energy platform of DESIREE to produce fragile molecular ions of biological and astrophysical interests, e.g., Rhodamine, and amino acids. A key feature of this source is a cryogenically cooled ring electrode trap, from which short, intense bunches of internally cold molecular ions are extracted.

Cold or Hot Reflex Discharge Ion Source (CHORDIS)

A CHORDIS (Model 921A, Gas version and Sputter version included) from Nordic Physics is under commissioning in the laboratory, several nA of B and Sm cation beam were obtained. This modular-designed CHORDIS can deliver high current beams of singly and multiply charged ions from a variety of gas and solid phase materials, seceral nA of cation beam from the low abundant isotopes like 36Ar and 38Ar were obtained. More information about the CHORDIS can be found from Nordic Physics.

Other Ion Sources

Currently, a hollow anode sputter source - the Baumann type source is also available at DESIREE. There is a plan to build a glow discharge source called JIMIS, a detailed description of JIMIS can be found on pages 14 to 18 in this Licentiate Thesis.

Gas cell and Charge-exchange Cell

Downstream of the high-energy beamline bending magnet, there is a gas-cell tube (70 mm long, 2 mm entrance and exit apertures) and a charge-exchange cell with a caesium oven. The gas cell can serve noble gasses such as He or Ar as collision partners while the latter is dedicated to serving caesium vapour for charge exchange.

Storage Rings, Beam Diagnostics and Detectors

Storage Rings

The DESIREE facility includes two storage rings with one common straight section. The symmetric ring has a four-fold symmetry while the asymmetric ring has a two-fold symmetry. The symmetric ring contains four 10° deflectors, two 160° cylindrical deflectors and four quadruple doublets. Ion beam with kinetic energy up to 35 keV can be stored in symmetric ring. The asymmetric ring has two common deflectors with the symmetric ring and can store ion beam with kinetic energy up to 100 keV. Depending on the beams’ energies the angle before and after the common deflectors vary between 0.5° and 10°, this is then compensated with the chicane deflectors before and after the common section.

There are five ion-laser interaction pathways in total, three perpendicular interaction pathways in the centre of each injection section and the common section, and two co-linear pathways along the two injection sections through the RAES and RAEA detectors.

Beam Diagnostics

There are two types of beam diagnostics inside the ring chamber, the Faraday cups which measure the beam current and the pick-ups which measure the beam position after injection.
Faraday cups: There are two Faraday cups in each ring, S-cup1 (A-cup1) to measure the current before storage and S-cup2 (A-cup2) to measure the current either after on turn or at the end of storage. S-cup2 and A-cup2 are the main diagnostics for improving storage conditions. In the first two cases with DC beam we can measure currents down to 0.1 pA, in the third case with a short pulse at the end of the cycle the standard deviation of each measurement is in the order of 50 pA.
Pick-Ups (PU): The ion beam is bunched after injection, with a minimum gap of 1-2 μs (the time to switch the injection supply). The beam is then bunched for a couple of hundred turns before the beam becomes coasting. When a bunched ion beam passes a pick-up electrode, the amplitude of the mirror charge is reverse-proportional to the distance between the ion beam and electrode. Each set of pick-ups consists of four electrodes which measure the beam’s position in both horizontal and vertical directions. There are in total four sets of pick-ups installed, one at the end of the injection section of each ring (S-PU, A-PU) and two at the beginning and end of the common section (PU1 and PU2).
There is also one Schottky pick-up in each ring; a cylindrical pick-up which only measures the total intensity. They can also be used for a coasting beam where one uses the individual signal from each ion.
Apertures: In order to lock the position of stored ion beam as well as to improve the overlap of two beams, two sets of apertures with inner diameter varying from 30 to 1 mm are installed between the 10° deflectors and the pick-ups in the common section. Merged beams experiments are set up by storing the beams with smaller and smaller apertures while the current in the Faraday cups are optimized.

Detectors

There are currently four detectors around the two rings, IMaging Detector (IMD), Fragment Detector (FD), Resistive Anode Encoder - Symmetric ring (RAES) and Resistive Anode Encoder - Asymmetric ring (RAEA). The IMD consists of three stacks of 75 mm diameter low-resistance Micro-Channel Plates (MCPs) backed by a phosphor screen. The light spots of the phosphor screen are transported out of the vacuum chamber and recorded by a 256×256 array fast camera called TPX3Cam from Amsterdam Scientific Instruments. IMD has the multi-hit capability for coincidence measurement of multiple particles.
The movable FD consists of 40 mm low-resistance MCPs backed by a resistive anode. The movable RAES and RAEA, in addition to the same MCPs and anodes like FD, employed two graphene-coated glass plates to allow for merged ion-laser experiments. The FD, RAES and RAEA detectors are position sensitive and with a dead time of some μs. All low-resistance MCPs mentioned above were specially made by Photonis to adapt to the cryogenic temperature of DESIREE storage rings.

Continues-Wave and Pulsed Laser Devices

SolsTiS and SolsTiS Doublet

The SolsTiS (type 4000, to be upgraded to type 5000) is a continuous-wave Ti:Sapphire laser from M Squared Lasers, it offers continuous tuning from 700 to 1000 nm, output power up to 4 W, ultra-narrow linewidth ≤ 50 kHz. The SolTiS Doublet is a fully automated second-harmonic generation module, it delivers continuous tuning from 350 to 500 nm together with SolsTiS, more information about the SolsTiS and SolsTiS Doublet can be found on their datasheets.

EKSPLA NT342C and NT242

There are two tunable Nd:YAG laser devices NT342C-10-SH/SFG/DUV (referred as NT342C hereafter) and NT242-1k-SH/SF-FC-SCU (NT242) from EKSPLA. The NT342C contains an integrated Optical Parametric Oscillator (OPO) system offering ultrabroad tuning range from 192 to 2600 nm, it has a repetition rate of 10 Hz and pulse duration of 3-5 ns, linewidth ≤ 5 cm−1. The figure on the right gives the pulse energy of NT342C.

The NT242 offers a tuning range from 210 to 2600 nm and a repetition rate of 1 kHz, integrated frequency divider can reduce its repetition rate to 500, 333, 250, 200 Hz, ... etc. The output power of NT242 is similar to that of NT342C, which means the output pulse energy is about two orders of magnitude less compared to that of NT342C.

Other lasers

Besides the above laser devices often ready to use, there are two laser devices in backup, Matisse TS Laser (a Ti:Sa CW Ring Laser from SIRAH LASERTECHNIK) and MIL-W-2796 (2796 nm, CW, 150 mW from PHOTONIC BERLIN).